1. Field of the Invention
The present invention relates to a name resolution device and a name resolution method for appropriately updating a name of each node on a network.
2. Description of the Related Art
In recent years, the world's largest computer network called internet has been spreading rapidly, and new computer businesses have been developed by utilizing information or service publicly disclosed by being connected to the internet, or conversely by providing information or service to external users who make accesses through the internet. There are also development and evolution of new techniques regarding the internet utilization.
On the internet, each computer has an identifier called IP address, and the packet exchanges are carried out based on this IP address. However, the IP address is a numerical value, which is not intuitive for a direct use by the human being so that it lacks the convenience. For this reason, a mechanism for converting the IPv6 address into a character string that is easier to handle for the human being, that is “name”, has been used. Currently, the most widely utilized conversion mechanism on the internet is DNS (Domain Name System).
The DNS is used for a global name resolution on the internet, so that a name FQDN (Fully Qualified Domain Name) used by the DNS must be uniquely defined on the internet.
On the other hand, due to the spread of the internet, the need for every node to have a globally unique name is diminishing. Also, in the DNS, because of its name disclosure property, it is impossible to publicly disclose a name of some node only to specific members. Consequently, what name does some domain have can be discovered by the brute force, and a malicious third person can easily acquire information regarding nodes with what names are existing. This causes the problem of the privacy leakage. In addition, in order to utilize the FQDN, there is a need to provide a DNS server for managing that FQDN, and this gives rise to the problem of the arranging location, the management, the registration, and the running of this server.
On the other hand, for a small network such as a home network, there are some propositions for a technique of defining a name locally on the network and making access to a node by using that name.
However, these techniques presuppose that the correspondent specified by the name is located in proximity from a viewpoint of the network, and they cannot be directly utilized in the case of attempting to make an access by using the name from an external of that network. In this case, a dedicated server responsible for the resolution from the external is required, or a protocol for discovering the server for that purpose is required, so that the user's convenience is damaged.
In order to avoid these problems, it is possible to use a method for utilizing a node local database. For example, in the OS such as Unix™, this is well known as “/etc/hosts” file.
In the case where some individual wishes the others to make accesses, it is possible to inform the name to the others by a method of exchanging data on address and name directly. However, the static database must be updated manually.
On the other hand, in the IPv6, it is expected that the renumbering will occur even in a small network such as a home network. Here, the renumbering implies the change of a network prefix to another value on some network.
This renumbering definitely occurs in the IPv6 when the user changed a provider, for example, because an address is basically assigned from a provider. At this point, in the case of utilizing the static node local database and information in the database has already been informed to someone, the occurrence of the renumbering must be informed, but there arises a problem of “who should be information of what” from a viewpoint of the privacy leakage. Namely, when an individual who has a node having two names of “foo” and “bar” on the network informs the name of his own node on the network to the others, there can be cases where it is desired to inform only “foo” to some people and inform only “bar” to some other people. In such a case, after the renumbering occurs, there arises a problem of “who should be informed of what”.